A federal appeals court has tossed out a Portland man's defamation lawsuit against a woman who accused him of sexual assault, citing an Oregon law designed to discourage suits that impinge on free expression.

In a decision issued last week, the 9th U.S. Circuit Court of Appeals panel reversed a lower court's ruling that would have allowed the case to proceed. The panel ruled that Oregon's law has bearing in the federal courts and that the man hadn't met a minimum burden of proof for his allegations.

The ruling buttresses Oregon's anti-SLAPP law, a statute written to short-circuit frivolous lawsuits filed only to discourage public expression. SLAPP stands for a "strategic lawsuit against public participation."

Additionally, the ruling could add a level of legal defense for any Oregonian who makes a criminal accusation.

"It's a great ruling in support of the anti-SLAPP statute and to protect people who have every right to express themselves," said Dan Booth, a Massachusetts attorney who represented the woman in court.